Hmm. It would probably be pretty cool but, as you say, have a number of potential problems. I'd be too afraid to use it for a neck, not only because of those problems but mostly because of the fear that I would end up wishing I had used it for something else.

What would be other common uses for a billet of ebony? Before I cut it up for frretboards, I'd like to know if it had a value to some other craft in billet form. You may be able to sell it and put the money towards even more fretboards (and not have to shoulder the risks associated with milling it up).

I would use it for fretboards. It isn't that stable and it would move if used for a neck, if you ask me. And it's heavy. There are better woods for necks, and you never have enough ebony for fretboards!

In the final days of the Henri Selmer guitars, they made a few with rosewood neck shafts. Selmer fans know about these and there is an oh-wow, ROSEWOOD neck thing about them. I played one 4-5 years ago, however and was not impressed. Who knows if the neck is to blame but the sound was thin and without much life. I had the feeling the notes were dying on the neck. It made an impression on me and I have favored light weight necks ever since.